I would say for self defence it gives you the option to scale your attack. Throwing someone on their head on concrete has a good chance to seriously concuss or kill them, so not a good idea in most cases. Remember most deaths in street fights are accidental when the guy gets knocked out and his head hits the floor when he drops. Throwing them with force would be even worse. A hard slam on their back will be enough to do it.
From my experience people who have never trained a grappling art are very easy to throw. Even 'big' guys like 200+ pounds it is really nothing to use leverage to throw them, boxers, kickboxers etc are usually quite helpless against this if you get in close.
Judo is really the only grappling art you can use against multiple attackers as you can easily throw or sweep someone and remain standing to take on the next guy.
Alot of the time though simply roughing them up or using a standing hold like a guilotine/ front face lock or standing arm triangle would do nicely if it is 1 on 1, and here again Judo excels in the standing grappling and control department compared to for example BJJ.
So yes, if it is very serious and your against someone much larger, or your getting your ass kicked standing against a striker and it is hard to get the standing sub, or there is more than one opponent in a self defence situation then by all means Osoto gari the mofo and most likely he will be out cold or winded/hurt. However be prepared he may get badly injured, even here you may want to reduce the force you use and practice to aim so the back or upper back hits not the back of the head.